This invention relates to the art of multiple-glazed windows and more particularly relates to multiple-glazed windows having reflective, transparent coatings of films disposed on a transparent sheet thereof.
Multiple-glazed windows have been used for many years to reduce the loss-or-gain of heat through windows. This object has been achieved by taking advantage of the fact that dry, essentially static gas, usually air, which is maintained in an enclosed space between spaced, generally parallel, sheets (panes or panels) of glass, acts as an effective insulator or thermal barrier. The static, dry air has a relatively low thermal conductivity.
Multiple-glazed windows may be constructed by joining two sheets of glass about their edges or margins in a spaced manner using a marginal spacer between them and a marginal frame around them. The spacer may be a rigid element, such as a metal spacer, or may be a compressible element, such as an organic plastic spacer. The glass sheets may be clear glass, may be colored glass or may be colored, heat-absorbing glass as defined by Federal Specification DD-G-45A (glasses which at a thickness of 1/4 inch transmit less than 50 percent of the total incident solar energy). The glass may be laminated, heat-strengthened or tempered. One or more coatings or films may be disposed on one or both sheets of glass. The coatings may be metal, metal oxide or combinations thereof; they may be electroconductive or highly resistive. As described in U.S. Pat. Nos. 3,609,293, 3,629,554 and 3,710,074, all to John L. Stewart, the interior sheet of glass may be provided with an electroconductive tin oxide film as the exterior sheet of glass is a coated or uncoated sheet of colored or heat-absorbing glass. In the last of these patents the patentee discloses and claims the effect of a reflective film on the exterior sheet of glass as an effective iridescence mask for a tin oxide film on the interior sheet of glass.
With the current interest in conserving energy there has developed a great impetus toward making windows which are improved summertime insulators in order to reduce air conditioning loads. It has been an objective to devise windows which are relatively inexpensive as well.
This invention is directed toward such a window.